Stack machine with improved cache memory for variables

A data processing system having a program structure and execution mode where an actual argument is bound to a formal argument of a function to be called by storing a pair of a variable name as the formal argument and a variable as the actual argument into a First-In-Last-Out stack memory as an environment list, the function called executes processings using a latest bind value from said environment list when referring to variable values, when a value of such a function is obtained, said function value is returned by deleting the formal argument variable of the function from said environment list, said system comprising:

• an associative buffer memory having entries, where each entry is formed of a pair of the variable name and a bind location address data for such variable on the environment list;
• and
• control means, for searching said associative buffer memory when variables are referenced using the variable name as the key, when the name variable exists in said associative buffer memory, for obtaining the variable value by the random access of the environment list using said bind location address, but when no variable name exists in said associative buffer memory, for searching said environment list associatively using the variable name as the key and using the variable value found and for storing the variable name and the address on the environment list as a pair in said associative buffer memory, when binding such argument on the occasion of calling a function, for storing a pair of an argument name and a bind value in said environment list and simultaneously for deleting said associative buffer memory entry where the argument name and name match, when a function is returned from call, for deleting both a pair of the argument name and the bind value from said environment list and the entry within said associative buffer memory having the location address on the environment list.

A data processing system having a program structure and execution mode where an actual argument is bound to a formal argument of a function to be called by storing a pair of a variable name as the formal argument and a variable as the actual argument into a First-In-Last-Out stack memory which contains an environment list, the function called executes processings using a latest bind value from said environment list when reinforcing variable values, when a value of such function is obtained, said function value is returned by deleting the formal argument variable of the function from said environment list, said system comprising:

• an associative buffer memory having words, where each word comprises a set of a variable name, a variable value and location data on said environment list to which the variable is bound;
• and
• control means, for searching the associative buffer memory when the variable is referenced using the variable name as the key, when the variable name matches the variable names being stored, for using the corresponding variable value by reading it, but if there is no match, for searching variable names on said environment list and for storing the variable name and the variable values along with the location data on said environment list into the associative buffer memory along with an operation identifier indicating where the latest variable value to be found is used, and when a function is called, for deleting the word which contains the name which matches the argument variable name, when a variable value is to be altered, for altering said latest bind value on the environment list and simultaneously if such variable exists therein, altering such variable value, and when a function returns from the call, for deleting a pair of the argument name and bind value from said environment list and simultaneously deleting the corresponding word from the associative buffer memory with the location data on the environment list used as the key.

A data processing system generating a variable name, comprising:

• an associative buffer memory storing variable names and addresses of the variables corresponding to each of the variable names;
• a pointer register operatively connected to said associative buffer memory;
• a stack memory, operatively connected to said pointer register, for storing the variable names and variables;
• and
• control means for loading the address of the variable into said pointer register and reading the variable out of said stack memory in dependence upon the address loaded into said pointer register when the variable name is applied to said associative buffer memory and the variable name exists in said associative buffer memory, and when the variable name does not exist in said associative buffer memory for incrementing said pointer register until said pointer register contains the address of the variable name and reading out the variable from said stack memory in dependence upon the incremented address in said pointer register.